If logistical and market factors are eliminated from the picture, one could effectively argue that the low cost of seed fungicides and the good they can do, make treating seed with a fungicide a good “insurance” investment for soybean producers. Just like car or life insurance, you don’t necessarily expect to recoup your investment in insurance premiums, but when you need the insurance it is there. Similarly, all soybean fields are subject to situations (minor herbicide or fertilizer injury, cool/wet/temporarily saturated soils, insect damage, soil crusting, planting too deep or variable planting depth, planting less than high quality seed, etc.) which can increase the potential for seed and seedling diseases to reduce stands. Your management style, and risk aversion strategies, will likely decide if the insurance analogy applies to your farm operation or not.
In any event, the benefits of seed treatment are most likely to be realized in the following situations:
• Soybeans planted mid-April to early-May, especially no-till or minimum till with abundant crop residue.
• Fields with a history of post-planting problems (minor soil crusting, temporary flooding, soil compaction, poorly drained soils).
• When low seeding rates are used.
• When seed planted is of moderate germination or the germination rate is unknown (note: use of seed of unknown or low germination is strongly discouraged).
• When precision of seeding rate, fertilizer application and/or herbicide application cannot be assured.
• Where Phytophthora is a historical problem, in which case a Phytophthora-tolerant soybean cultivar should be planted that has been treated with either metalaxyl- or mefanoxam.